1. Field of the Invention
The present invention relates to a high strength sintered body using a high pressure form boron nitride incorporated therein.
2. Description of the Related Art
cBN is the hardest material next to diamond. cBN-based sintered bodies are used in various cutting tools, abrasion-resistant parts etc.
This kind of sintered body can hardly exhibit a high hardness and a high strength at the same time. Techniques for satisfying the two requirements at the same time are described in, e.g., JP-B-62-25630 (The term "JP-B" as used herein means an "examined Japanese patent application"), JP-B-62-25631 and JP-A-5-186272 (The term "JP-A" as used herein means an "unexamined published Japanese patent application").
However, the foregoing various techniques are not necessarily sufficient with respect to the simultaneous accomplishment of the two requirements. In particular, these techniques leave something to be desired in strength under severe cutting conditions as in interrupted cutting of hard to cut materials.